JP2001116889A - Device for processing radioactive gas waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently operate a dehumidifier by controlling the number of units to be operated, according to the amount of gas processed during each operation. SOLUTION: In a processing device for radioactive gas wastes, exhaust gas from a main turbine condenser is recombined with hydrogen gas by a hydrogen recombiner 2 and is processed for reducing its volume and is dehumidified by the dehumidifier 6 located downstream thereof; radioactive gas remaining in the exhaust gas is adsorbed by an activated charcoal type rare gas holdup tower 7 and the exhaust gas is released into the atmosphere from an exhaust cylinder 9. The dehumidifier 6 comprises a plurality of dehumidifier units 38 connected in parallel with one another, each of the dehumidifier units 38 comprising a plurality of hollow yarn membrane modules 39 connected in parallel with one another, each of the hollow yarn membrane modules 39 comprising a multiplicity of hollow yarn membranes 40 bound and stored in a sealed container. A line and a valve are connected to each of the hollow yarn membrane modules 39.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for treating radioactive gas waste having an improved dehumidification system in a dehumidifier for removing moisture from exhaust gas from a hydrogen recombination apparatus.

[0002]

2. Description of the Related Art In general, a coolant in a boiling water reactor is irradiated with neutrons while passing through a reactor core, and is partially decomposed into oxygen and hydrogen, and furthermore, ³ H, ¹⁶ N, ¹⁹ O and the like occur. In addition, Kr and Xe
Such radioactive rare gases leak, and these rare gases are mixed into the coolant and sent to the turbine system. In addition, there is leakage from outside air into the turbine main condenser.

[0003] Due to these radioactive gas wastes (hereinafter simply referred to as exhaust gas), it is necessary for the turbine system in the boiling water nuclear power plant to provide the same shielding equipment as the nuclear reactor and maintain the soundness inside and around the plant. is there.

Since exhaust gas is generally non-condensable, it stays in the steam system, particularly in the main turbine condenser. Therefore, conventionally, exhaust gas remaining in the turbine main condenser is extracted by an air extractor and guided to an activated carbon hold-up tower for processing.

FIG. 3 shows an example of a conventional radioactive gas waste treatment apparatus of this type. That is, in FIG.
Reference numeral 1 denotes an air extractor. Exhaust gas retained inside the turbine main condenser is bled by the air extractor 1, and a preheater 3,
The hydrogen gas is led to the hydrogen recombining device 2 composed of the recombiner 4 and the condenser 5 and recombines and reduces the volume of the hydrogen gas.

The exhaust gas guided to the hydrogen recombining device 2 is first preheated by the preheater 3 to a temperature at which oxygen and hydrogen contained in the exhaust gas efficiently recombine, and then guided to the downstream recombiner 4, Hydrogen and oxygen in the exhaust gas are converted into steam by a recombination reaction. Further, in the condenser 5 downstream thereof, the steam in the exhaust gas is condensed by the cooling water by the external cooling water to become almost water and separated from the exhaust gas, and the separated water is returned to the turbine main condenser.

On the other hand, the exhaust gas from which water has been separated and removed is shown in FIG.
As shown in (1), it is guided to the dehumidifier 6 to perform dehumidification, and then guided to the activated carbon type rare gas hold-up tower 7.
The radioactive gas remaining in the exhaust gas (mainly Xe, K
Rare gas such as r) is adsorbed on activated carbon, and after a long hold-up, is discharged from the exhaust pipe 9 to the atmosphere by the vacuum pump 8.

[0008] Each of these devices is separated into airtight or similar rooms, and each room is air-conditioned. In particular, as shown in FIG. 3, the activated carbon-type noble gas hold-up tower room 10 is air-conditioned from a dedicated air-conditioning facility 11 via an air supply duct 12 and an exhaust duct 13 separately from other general air-conditioners.
In order to maintain the adsorption performance of activated carbon, the inside of the activated carbon type rare gas hold-up tower inlet pipe 14 can be kept at a low temperature.

FIG. 4 shows details around the dehumidifier 6 shown in FIG. 3. Each dehumidifier 6 is a single unit, for example, 40 Nm ³ / h.
In order to treat the exhaust gas of the above, it is constituted by a container in which ten or more hollow fiber membrane modules 17 are incorporated. These are inlet valves
It is connected in parallel via 15 and an outlet valve 16, and during normal operation, only one of the systems performs the processing operation, and the other system is reserved.

That is, as shown in FIG. 4, each of the dehumidifiers 6 includes a plurality of hollow fiber membrane modules 17 in units of several tens of
Even if the amount of treatment is extremely reduced due to fluctuations in the exhaust gas flow rate due to the difference in operation mode, one dehumidifier will be used, and it is difficult to respond efficiently. .

In FIG. 4, the dehumidifier 6 is a storage container.
24, an upper tube plate 25, a lower tube plate 26, an upper cover 27, a lower cover 28 connected to the upper and lower portions of the containment container 24, and a hollow fiber membrane provided between the upper tube plate 25 and the lower tube plate 26. It consists of module 17.
The upper tube sheet 25 and the upper cover 27 and the lower tube sheet 26 and the lower cover 28 are airtightly connected by a flange 29, respectively.

[0012]

In the conventional radioactive gas waste treatment apparatus, it is necessary to equip the hollow fiber membrane module 17 capable of covering the maximum load in the design, so that the apparatus cannot be overspecified. I didn't get it. In addition, a large number of dehumidifying hollow fiber membrane modules are used to support the maximum set flow rate.
Exhaust gas is processed by the dehumidifier 6 with the built-in 17. That is, the dehumidification of the maximum processing capacity is performed when the system flow rate is greatly increased (eg, about 80 Nm ³ / h) such as at the time of starting, or when the system flow rate is extremely reduced as usual (eg, about 4 Nm ³ / h). There is a problem that the dehumidifying efficiency has to be extremely reduced due to the need to cope with the device.

Also, when disassembling the dehumidifying device 6 at the time of the periodic inspection, it is necessary to pay close attention to the disassembly of the large storage container 24 and the detachment and attachment of a large number of hollow fiber membrane modules 17, as well as to the ease of disassembly. However, there is a problem that requires a lot of work time.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and can efficiently control the amount of a hollow fiber membrane module to be used in response to a change in the amount of exhaust gas. It is an object of the present invention to provide a radioactive gas waste treatment apparatus that can be operated efficiently in response to a change in the amount of processing gas during operation by being able to easily replace only the membrane module, and that can achieve high reliability and economy. Aim.

[0015]

According to the first aspect of the present invention, a radioactive gas waste generated from a nuclear power plant is led from a main condenser through an air extractor to a hydrogen recombination device to recombine hydrogen gas. After reducing the amount of hydrogen in the exhaust gas to the flammable limit or less and performing volume reduction processing, the exhaust gas treated by the hydrogen recombination device is led to the dehumidifier to perform dehumidification,
Next, in the treatment apparatus for radioactive gas waste that leads to an activated carbon type rare gas hold-up tower to attenuate radioactivity, the dehumidifier is a device in which a plurality of dehumidifier units are arranged and connected in parallel, and the dehumidifier unit is A plurality of hollow fiber membrane modules each containing a large number of hollow fiber membranes bundled and stored in a sealed container are connected in parallel and connected, and each of the plurality of hollow fiber membrane modules has a pipe and a valve. It is characterized by being connected.

According to the first aspect of the present invention, unlike a conventional dehumidifier in which a large number of hollow fiber membrane modules are incorporated in a can body, a large number of hollow fiber membranes are bound and housed in a sealed container. The hollow fiber membrane module is used as a dehumidifying unit in units of several hollow fiber membrane modules, and a plurality of the dehumidifying units are arranged in parallel. Thus, the number of dehumidifying units that are operated according to the amount of processing gas during each operation can be controlled, and the dehumidifying device can be used effectively. That is,
It is possible to optimally cope with fluctuations in the exhaust gas flow rate due to the difference in the operation mode, and to cope with a case where the unit needs to be switched due to a trouble in the dehumidifying unit in use. In addition, since the device is not a dehumidifier that incorporates a large number of hollow fiber membrane modules into a can body, the response at the time of maintenance is simplified.

According to a second aspect of the present invention, the main condenser is connected to the secondary side of the hollow fiber membrane module so that a part of the primary gas dried by the dehumidifying unit is supplied for purging. When the vacuum pressure of the main condenser is low, such as at the time of plant start-up, or the pressure of the secondary condenser is lower than the primary pressure by the purge vacuum pump provided on the upstream side of the main condenser. It is characterized in that it is connected to a pipe so as to suction to a pressure and provide a partial pressure difference of steam between the primary side and the secondary side of the hollow fiber membrane module.

According to the second aspect of the present invention, a part of the primary gas dried by the dehumidifying unit is used on the secondary side of the hollow fiber membrane module for purging, and the vacuum pressure of the main condenser is reduced. When the vacuum pressure of the main condenser is low, such as at the time of plant startup, or by suctioning the secondary side to a pressure lower than the primary side pressure with a vacuum pump for purging, the primary and secondary sides of the hollow fiber membrane module are By providing the partial pressure difference of the steam, the dehumidifying performance can be improved.

A third aspect of the present invention is characterized in that a moisture removing device is installed in a stage preceding the dehumidifying unit. According to the third aspect of the present invention, a part of the primary gas dried by the dehumidifying unit is used as a purge gas of the dehumidifying unit for removing moisture and the like which may deteriorate the performance of the hollow fiber membrane module. Alternatively, dried gas in the plant (eg instrumentation air, etc.) can be used.

According to a fourth aspect of the present invention, when humidity below a required percentage cannot be obtained due to the state of the dehumidifying unit, the humidity is detected by a dew point meter installed downstream of the dehumidifying unit and used. The dehumidifying unit may be switched to a non-humidifying unit, or may be switched to a circulation line system to the main condenser to connect a pipe so as to prevent the flow of the wet gas to the downstream.

According to the fourth aspect of the present invention, when humidity below a required percentage cannot be obtained due to the state of the dehumidifying unit, the humidity is detected by a dew point meter installed in the system, and the dehumidifying unit not used is used. Can be switched to

If the dehumidification system becomes defective and the dehumidification performance cannot be ensured, the humidity is detected by a dew point meter installed in the system, and the system is switched to a circulation line system for the main condenser to obtain a wet gas. Can be prevented from flowing downstream, and the radioactive gas waste treatment system can be protected.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a radioactive gas waste treatment apparatus according to the present invention will be described with reference to FIGS. This embodiment is a method for dehumidifying exhaust gas flowing into a dehumidifying unit incorporating a hollow fiber membrane, a dehumidifying unit switching system and an emergency switching system that optimally respond to fluctuations in exhaust gas flow due to differences in operation modes. Although having a feature, the processing apparatus for the radioactive gas waste in other parts is the same as the conventional exhaust gas processing apparatus shown in FIG. Therefore, in the present embodiment, the description of the same parts as the conventional example will be omitted.

FIG. 1 is a system diagram showing the configuration around the dehumidifying unit 28 in the radioactive gas waste treatment apparatus according to the present embodiment, and FIG. 2 is a system diagram showing the dehumidifying unit 38 in FIG. In FIG. 2, the dehumidifying unit 38 is a unit in which a plurality of hollow fiber membrane modules 39 formed by bundling a number of hollow fiber membranes 40 are connected in parallel.

As shown in FIG. 1, the dehumidifying apparatus in this embodiment is provided with four dehumidifying units 38 arranged in parallel, and one pipe is provided for each of the exhaust gas inlet and outlet and the system air inlet and outlet. Is connected to Note that the number of dehumidifying units 38 is not limited to four.

An exhaust gas inlet side of each dehumidifying unit 38 is connected to a moisture removing device 36, and the moisture removing device 36 and the recombiner 4
Between the condenser outlet thermometer 30, the condenser outlet pressure gauge 31,
A dehumidifying unit inlet flow meter 34 and a dehumidifying unit inlet flow rate adjusting valve 35 are connected, and branch from between the condenser outlet pressure gauge 31 and the dehumidifying unit inlet flow meter 34 to form a condenser outlet circulation line valve 32. The condenser circulation line pressure regulating valve 33 is connected.

On the exhaust gas outlet side of each dehumidifying unit 38, a dew point meter 56, a dehumidifying unit outlet pressure gauge 57, a dehumidifying unit outlet flow meter 58, a dehumidifying unit outlet flow regulating valve 59, and an activated carbon type rare gas hold-up tower inlet valve 60 are provided. Is connected. The dehumidifying unit outlet circulating line valve 61 and the dehumidifying unit outlet circulating line pressure regulating valve 62 are connected to branch from between the dehumidifying unit outlet pressure gauge 57 and the dehumidifying unit outlet flow meter 58.

Further, the system gas (purge gas) outlet side of each dehumidifying unit 38 has a purge gas outlet valve 48, a purge gas pressure gauge 49, a purge gas pressure regulating valve 50, and a main condenser inlet valve 51.
Is connected. Branched from between the purge gas pressure regulating valve 50 and the main condenser inlet valve 51, the purge vacuum pump inlet valve 5
2. A purge vacuum pump 53, a purge vacuum pump outlet check valve 54, and a purge vacuum pump outlet valve 55 are connected.

In FIG. 2, three hollow fiber membrane modules 39 connected in parallel are connected to a dehumidifying unit inlet valve 37 and a dehumidifying unit outlet valve 41. Dehumidification unit outlet valve
A dehumidifying unit purge gas valve 42, a dehumidifying unit outlet purge gas check valve 43, a purge gas inlet check valve 45, and a purge gas inlet valve 44 are connected to branch from between the 41 and the activated carbon type rare gas hold-up tower 7.

The purge gas check valve 43 and the purge gas inlet check valve 45 are branched from the purge gas check valve 43 and the purge gas flow meter 46 and the purge gas flow control valve 47 are connected. The purge gas flow control valve 47 is hollow through a pipe. It is connected to the thread membrane module 39. The purge gas inlet valve 44 is connected to the system air piping. The purge gas outlet side of the hollow fiber membrane module 39 is connected to the main condenser inlet valve 51.

The number of operating dehumidifying units 38 can be controlled from one dehumidifying unit 38 to all (in the illustrated example, four) dehumidifying units 38 by the operation mode and the exhaust gas flow meter 34 connected to the upstream side. I have.

For example, the set capacity of one dehumidifying unit 38 is 20 Nm ³ / h, and the dehumidifying unit 38
20Nm during normal operation
³ / h or less, one dehumidifying unit 38 can perform sufficient treatment, and the remaining three dehumidifying units 38 can be used as spares in an emergency. In the operation in the high flow rate mode at the time of starting the plant, a processing amount of, for example, about 80 Nm ³ / h is required, and all four dehumidifying units 38 are used.

As shown in FIG. 2, each hollow fiber membrane module 39 has a hollow fiber membrane 40 having a large water vapor permeability coefficient housed in a sealed container (not denoted by a reference numeral), and is provided above and below each sealed container. The pipe and the valve are connected, and the exhaust gas sucked by the vacuum pump 8 shown in FIG. 3 passes through each of the hollow fiber membranes 40.

The temperature of the exhaust gas flowing to each dehumidifying unit 38 is measured by a condenser outlet thermometer 30 provided on the outlet side of the condenser 5 as shown in FIG. 50 ° C) or above.
Alternatively, the condenser outlet circulating water line valve 32 is opened to circulate to the main condenser side so that exhaust gas does not flow to the dehumidifying unit 38.

The system pressure is measured by a condenser outlet pressure gauge 31 provided between the condenser outlet thermometer 30 and the dehumidifying unit inlet flow meter 34, and is measured to be higher than the system operation set pressure (for example, atmospheric pressure). , The condenser outlet circulating water line valve 32 is opened, and the condenser outlet circulating water line pressure regulating valve 33 provided downstream thereof is adjusted to keep the system pressure within the set value.

The flow rate suitable for the throughput of each dehumidifying unit 38 is ensured by adjusting the dehumidifying unit inlet flow rate regulating valve 35 by the dehumidifying unit inlet flow meter 34, and the system is stably operated. On the upstream side of the dehumidifying unit 38, there is provided a moisture removing device 36 for removing moisture in the system during operation and preventing the performance of the dehumidifying unit 38 from deteriorating due to adhesion of water droplets.

In order to prevent the adhesion and retention of water in the hollow fiber membrane module 39, the flow of the exhaust gas is transferred from the water removal device 36 to the activated carbon type rare gas hold-up tower 7 using an upper float (flow from bottom to top). ), The hollow fiber membrane module 39 is installed vertically and connected by piping.

As shown in FIG. 2, each dehumidifying unit 38 uses a part (for example, 15% or more) of the primary gas dried by the hollow fiber membrane module 39 in the dehumidifying unit 38 for purging. An amount corresponding to, for example, about 15% or more of the exhaust gas processing amount measured by the dehumidifying unit inlet flow meter 34 shown in FIG. 1 by the flow meter 46 is ensured by adjusting the purge gas amount adjusting valve 47.

If the operation of the dehumidifying system is not stable at the beginning of the operation, the dehumidifying unit purge gas valve 42
Is closed and the purge gas inlet valve 44 is opened, so that a part of the primary gas dried by the dehumidifying unit 38 is used as a purge gas instead of a dried gas (for example, instrumentation air) in a nuclear power plant. Etc.) so that driving is not hindered.

The pressure of the purge gas is controlled by the purge gas pressure gauge 49 so that the pressure of the purge gas is adjusted by the purge gas pressure regulating valve 50, and the pressure of the purge gas is reduced by the vacuum pressure of the main condenser. Has become.

When the vacuum pressure of the main condenser is low, such as when the plant is started, the main condenser inlet valve 51 is closed, and the purge vacuum pump inlet valve 52 and the purge vacuum pump outlet valve 55 are opened. By driving the purge vacuum pump 53 to set the purge gas pressure to a negative pressure, suction is performed at a pressure lower than the primary side.

As a result, the water vapor in the exhaust gas flowing through each hollow fiber membrane 40 passes through each hollow fiber membrane 40 and is separated and removed, so that the relative humidity of the exhaust gas becomes a required percentage, for example, 40% or less. ing. The purge gas can also be selected by switching the purge gas inlet valve 42 and the purge gas outlet valve 47 for the operation system of the processing unit.

Next, a method of removing moisture in each dehumidifying unit 38 will be described. In FIG. 1, the exhaust gas from the recombiner 4 is cooled by steam in a condenser 5, and the condensed exhaust gas is discharged by a vacuum pump 8 (see FIG. 3) for sucking the system.
Excess water in the exhaust gas is removed through the water removal device 36 and guided to the dehumidification unit 38 through the dehumidification unit inlet valve 37 shown in FIG.
Pass through.

At this time, the inside of the hollow fiber membrane module 39 is adjusted to an appropriate flow rate of the dried purge gas by the purge gas amount control valve 47, and flows into the inside of the hollow fiber membrane module 39 (outside the hollow fiber membrane 40). Improve transparency.

Further, the inside of the hollow fiber membrane module 39 (outside of the hollow fiber membrane 40) is evacuated to maintain a pressure lower than the pressure of the primary system by utilizing the degree of vacuum of the main condenser. The pressure is adjusted by the purge gas pressure adjusting valve 50 according to the set value of the purge gas pressure gauge 49 via the purge gas outlet valve 48. As a result, appropriate evacuation is performed, so that water vapor in the exhaust gas flowing inside the hollow fiber membrane 40 is removed through the hollow fiber membrane 40 and discharged to the main condenser.

Therefore, the relative humidity of the exhaust gas after passing through the hollow fiber membrane module 39 becomes a required percentage, for example, 40% or less, and the activated carbon type rare gas hold-up tower 7 (through the dehumidifying unit outlet valve 41) (See FIG. 3) and delay processing is performed.

If a trouble or the like occurs in the dehumidifying unit 38 and the dew point meter 56 at the outlet of the dehumidifying unit 38 becomes larger than the set value, the dehumidifying unit inlet valve 37 and the dehumidifying unit outlet valve
41, the purge gas inlet valve 42 and the purge gas outlet valve 48 are closed. At the same time, another standby dehumidifying unit inlet valve 37, dehumidifying unit outlet valve 41, purge gas inlet valve 42, and purge gas outlet valve 48 are opened, and the system is switched to the standby dehumidifying unit 38 side.

If the dew point meter 56 exceeds the set value even after the system of the dehumidifying unit 38 is switched, the activated carbon type rare gas hold-up tower inlet valve 60 is closed and the outlet of the dehumidifying unit is circulated. The line valve 61 is opened, the circulation line to the main condenser is activated, and the safety of the system is ensured. In this case, the pressure of the dehumidification system is adjusted by the dehumidification unit outlet circulation line pressure adjustment valve 62.

[0049]

According to the present invention, a dehumidifying unit can be selected according to the flow rate of exhaust gas. For example, all the dehumidifying units are used at the time of high flow rate operation at the time of starting the plant, and at the time of normal operation. Control of the number of used units of the dehumidifying unit can be easily and effectively performed depending on the amount of exhaust gas to be treated so that one dehumidifying unit can cope with it. Further, the efficiency of system operation can be improved by subdividing the dehumidifying device.

The configuration of the dehumidifying unit is such that a plurality of hollow fiber membrane modules each having a pipe and a valve connected to each other are connected in parallel as a set. In particular, a large number of hollow fiber membrane modules are connected to a single unit as in the conventional example. Since it is not built in the can body, the installation space area is small, and it can contribute to effective use of the space.

Further, by using a hollow fiber membrane for filtering exhaust gas, maintenance work can be largely omitted, the economic efficiency is improved, and the reliability is improved by using a dynamic processing device, and the equipment is rationalized. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a configuration of a dehumidification system in a first embodiment of a radioactive gas waste treatment apparatus according to the present invention.

FIG. 2 is a system diagram showing a configuration around a dehumidifying unit in FIG. 1;

FIG. 3 is a system diagram showing a configuration of a conventional apparatus for treating radioactive gas waste.

FIG. 4 is a system diagram showing the periphery of the dehumidifier in FIG. 3;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Air extractor, 2 ... Hydrogen recombination device, 3 ... Preheater, 4
... Recombiner, 5 ... Condenser, 6 ... Dehumidifier, 7 ... Activated carbon type rare gas hold-up tower, 8 ... Vacuum pump, 9 ... Exhaust tube, 10 ... Activated carbon type rare gas hold-up tower room, 11 ... Air conditioning Equipment, 12, 13 duct, 14 activated carbon rare gas hold-up tower inlet piping, 15 dehumidifier inlet valve, 16 dehumidifier outlet valve, 17 dehumidifier hollow fiber membrane module, 18 dehumidifier purge gas inlet valve , 19 ... Purge gas flowmeter for dehumidifier, 20
... dehumidifier purge gas flow control valve, 21 ... dehumidifier purge gas outlet valve, 22 ... dehumidifier purge gas pressure gauge, 23 ... dehumidifier purge gas pressure regulator, 24 ... containment vessel, 25 ... upper tube plate, 26 ... lower tube plate, 27… Top cover, 28… Bottom cover, 29… Flange,
30… Condenser outlet thermometer, 31… Condenser outlet pressure gauge, 32… Condenser outlet circulation line valve, 33… Condenser outlet circulation line pressure adjustment valve, 34… Dehumidification unit inlet flow meter, 35… Dehumidification unit inlet flow control valve, 36 ... moisture removal device, 37 ... dehumidification unit inlet valve, 38 ... dehumidification unit, 39 ... hollow fiber membrane module, 40 ... hollow fiber membrane, 41 ... dehumidification unit outlet valve, 42 ... dehumidification unit purge gas Valve, 43: Dehumidification unit outlet purge gas check valve, 44: Purge gas inlet valve, 45: Purge gas inlet check valve, 46: Purge gas flow meter, 47: Purge gas flow control valve, 48: Purge gas outlet valve, 49: Purge gas pressure gauge ,
50… Purge gas pressure regulating valve, 51… Main condenser inlet valve, 52…
Vacuum pump inlet valve for purging, 53 ... Vacuum pump for purging,
54 ... Purge vacuum pump outlet check valve, 55 ... Purge vacuum pump outlet valve, 56 ... Dew point meter, 57 ... Dehumidifying unit outlet pressure gauge, 58 ... Dehumidifying unit outlet flow meter, 59 ... Dehumidifying unit outlet flow control valve, 60 ... activated carbon type rare gas hold-up tower inlet valve, 61 ... dehumidifying unit outlet circulating line valve, 62 ... dehumidifying unit outlet circulating line pressure regulating valve.

Claims (4)

[Claims] 1. A radioactive gaseous waste generated from a nuclear power plant is led from a main condenser through an air extractor to a hydrogen recombination device to recombine hydrogen gas, and the amount of hydrogen in the exhaust gas is combustible. After reducing the volume to below the limit and performing volume reduction treatment, the exhaust gas treated by the hydrogen recombination device is guided to the dehumidifier to perform dehumidification, and then to the activated carbon rare gas hold-up tower to reduce the radioactivity. In the apparatus for treating gaseous waste, the dehumidifying device is a device in which a plurality of dehumidifying units are arranged and connected in parallel, and the dehumidifying unit is a hollow fiber in which a number of hollow fiber membranes are bundled and stored in a sealed container. A plurality of membrane modules are arranged in parallel and connected, and the plurality of hollow fiber membrane modules are connected with a pipe and a valve, respectively. Processing equipment. 2. A pipe connection is made to a secondary side of the hollow fiber membrane module so as to supply a part of a primary gas dried by the dehumidifying unit for purging, and a vacuum pressure of the main condenser, or When the vacuum pressure of the main condenser is low, such as at the time of plant startup, the secondary side of the dehumidifying unit is suctioned to a pressure lower than the primary side pressure by a vacuum pump for purge provided on the upstream side of the main condenser. The radioactive gas waste treatment apparatus according to claim 1, wherein piping is connected so as to provide a partial pressure difference of steam between the primary side and the secondary side of the hollow fiber membrane module. 3. An apparatus for treating radioactive gas waste according to claim 1, wherein a water removing device is provided upstream of said dehumidifying unit. 4. When the humidity of a required percentage or less is not obtained due to the state of the dehumidifying unit, whether the humidity is detected by a dew point meter installed downstream of the dehumidifying unit and the dehumidifying unit is switched to an unused dehumidifying unit. 4. The treatment of radioactive gas waste according to claim 1, wherein the system is switched to a circulation line system to the main condenser and connected to a pipe so as to prevent the flow of the wet gas downstream. apparatus.